#include	<stdio.h>
#include	<string.h>
int main(int argc, char *argv[])
{
	char *a="255.255.255.255";	
	char b[16] = {0};
	memcpy(b, a, 16);
	int la = strlen(a);
	int lb = strlen(b);
	printf("la = %d\n",la);
	printf("lb = %d\n",lb);

	memset(b, 0 ,16);
	lb = strlen(b);
	printf("lb = %d\n",lb);
	printf("==================\n");
	char *c = NULL;
	printf("lc= %d\n",strlen(c));
	return 0;
}
